In wireless communication systems, very high frequency signals are transmitted from satellite, aircraft or land-based transmitters, and subsequently received as highly attenuated signals which may in turn be on land, in air or in space. Due to the effects of attenuation over distance, and the presence of interfering signals in the signal environment, the communication signals must be raised to a high level at the transmitter, and again restored to detectable levels at the receiver. The amplifiers used for this purpose in both transmitters and receivers, while differing in many details, nonetheless each involve several stages of signal amplification, often designed using Gallium Arsenide (GaAs)-based transistors and integrated circuits. For each amplifier stage, it is required to provide an appropriate D-C bias to the operating transistors, in the form of prescribed voltages and currents applied to the device terminals. Since the biasing needs of the various stages will, in general, be somewhat different, it has therefore been the usual practice to provide a separate biasing circuit as an integral part of each associated amplifier stage. Thus biasing circuits may represent a significant portion of the electronic content of the receiver.
In certain specific fields of application, such as satellite broadcast television, the low-noise receiver amplifiers are manufactured in large quantities, in a very competitive economy which drives continuing reductions in cost and price.